Currently, multi-hop wireless communication technology is one of the research and development hot spots in the field of wireless communication technology, and the multi-hop wireless communication systems represent a development trend for future wireless communication systems. For example, the Institute of Electrical and Electronics Engineers (IEEE) has established a Relay Task Group, to engage in the introduction of the concept of a relay station in a wireless communication system that is based on the standards of IEEE 802.16 series.
A strong advantage of the multi-hop wireless communication system is the adoption of relay stations. By the adoption of relay stations, the coverage of a base station in a conventional wireless cellular communication system can be significantly extended, and at the same time, a more flexible path selection can be provided for the communication between a base station and mobile stations. In this way, in a region where the coverage of a base station of a conventional cell is poor, or when the communication link between a base station and a mobile station is affected by shadow fading, by using a relay station to relay the communication between the base station and mobile station so as to change an originally single and fixed “single-hop” link between the base station and the mobile station into a “multi-hop” link that can be selected flexibly, the performance of the wireless cellular communication system can be improved significantly. Theoretically speaking, it can be simply considered that, when the number of relay stations in a multi-hop wireless communication system increases, the performance of this system will be greatly improved, as there are more communication paths for selection.
However, when the number of relay stations in the multi-hop wireless communication system increases continuously, a problem occurs at the same time in which the system overheads for managing these relay stations also increase continuously. In a multi-hop wireless communication system where the relay stations are managed in a centralized manner, both the communication link between abase station and a relay station and the communication link between a relay station and a mobile station need to be managed by the base station, and with the continuous increase in the number of relay stations, the signaling overheads for the link management in the base station will increase significantly, especially in the case of supporting the cooperative relay, the increase of the signaling overheads will be very significant.
For this reason, the concept of a distributed network is proposed in the multi-hop wireless communication system. The difference between this distributed network and the centralized management mentioned above is that, on the basis of the concept of a distributed network, a base station only manages the communication link between itself and the relay stations, while the communication link between a relay station and a mobile station is managed by the relay station itself. Although the distributed link management can reduce a part of signaling overheads for the link management by the base station, the base station still has to manage the communication link between itself and the relay stations, and therefore, when the number of relay stations increases, the increase of signaling overheads for the link management is inevitable.